According to CIES' model, the Real Madrid star is now far behind the world's most valuable player -- Neymar of Paris Saint-Germain's Neymar (€213 million), with Barcelona's Lionel Messi second (€202.2m) and Tottenham's Harry Kane (€194.7m) third.

Ronaldo's assigned value of €80.4m had him between Manchester United forward Anthony Martial and Monaco's utility man Fabinho in the top 100 list. Such a ranking from a respected organisation mandated by both FIFA and UEFA caused so much interest that a burst of traffic crashed the CIES website for a short time on Monday afternoon.

But according to CIES Football Observatory head Raffaele Poli hard data and past precedent suggest that the 32-year-old is just not worth as much as he used to be.

So what is included in the calculations?

The full methodology in determining their valuations is freely available on the Switzerland-based organisation's website and includes the level of the player's club, their potential suitors, age and performance in current season across different competitions, minutes played, international status and contract status.

"Looking at these different variables, you have a scientific algorithm which tells you what clubs have paid in the past for a player with these characteristics," Poli told ESPN FC. "It does not take into account inflation in the market, which is why we are quite close but a bit lower than the actual reported fees."

In Ronaldo's case the numbers were crunched the same as everyone else, and an objective price level was found.

"There are objective facts that explain [Ronaldo's valuation]," says Poli. "His age is the most important, but also Real Madrid have not performed that well, and Ronaldo himself has not scored so much, in the last few months."

What isn't included?

It immediately seems odd that someone who in the last six months has picked up a fifth career Ballon d'Or, second consecutive FIFA 'Best' individual prize and a third UEFA player of the season award could be so far down the ranking. But Poli says that such individual awards do not fit into CIES' model.

"The Ballon d'Or cannot be a significant variable [for the algorithm]," he said. "You cannot include something which only concerns one or a few players. That would distort the model."

Off pitch commercial activities would also be a huge part of Ronaldo's attractiveness to any club, but this added value is also beyond the scope of the CIES calculations. A player's current reported high wages, or wish for a salary rise, is not taken into account either.

"This is a model for transfer values," Poli says. "To build a model with wages we would need to know the players' real current wages, and you cannot find this so easily [even if the] media speak about that a lot."

But is Ronaldo, who says himself he plans to play until he is 40 and at 32 was the decisive player in last year's Champions League, not a special case?

"This is only speculation," says Poli with a laugh. "You have to expect him to take the general path of a player. He is the most valuable player of his age anyway [in the model]. Even though you may think he is not so high [in the ranking]."

Ronaldo has gone through early season slumps in past seasons too, before returning to form when it matters most. The example of teammate Gareth Bale, who does not even make the top 100 for CIES at the moment, shows how players' value can rise and fall over time.

"Minutes played is very important, and Bale has been injured all the time [recently]," says Poli. "His value is still almost €50m, and if he is back then it will increase of course. Then you have to look at age, Wales not being at the World Cup, which are minus factors. If he scores and does well in the Champions League it can change [again] quite heavily."

Ronaldo is now worth a lot less than the other top players in the world. Denis Doyle/Getty Images

"The Premier League is the wealthiest league, so in the end when a player goes to England there is a [extra] price," Poli says. "For English players in England the impact is even stronger, as there are not so many top level English players. So of course nationality is a factor that gives them a [extra] weight."

Younger players at top clubs who struggle for playing time see their value affected, explains Poli.

"[Asensio] does not play a lot, less than 1,000 minutes," he says. "He is not yet a starting XI player. In the end minutes and performance of the club are very important. That is why of Real Madrid you have Isco, who is playing a lot and his ranking is quite high.

"Even [Raphael] Varane, people say he is the best defender, but [Samuel] Umtiti is playing twice as much, and Barcelona are doing better than Real Madrid. So these are the facts. You can say I like this player, he should be [in the top 100], but we only look at facts, not subjectivity."

Fans might scoff at using such statistical analysis to make transfer market decisions. But Poli says that some clubs have approached CIES to use their algorithm while making transfer decisions, while others are building their own internal models using similar criteria.

"Some clubs claim to be trying to build [their own model]," he says. "Another club was interested in buying our algorithm but we did not sell it to them. There is now a recognition and a need for clubs to be quite accurate, given the incredible amounts at stake. We are a good partner for them, and quite transparent, so in some ways we do the job for them."